ASTM A335 P5

ASTM A335 P5, P5b & P5c Seamless Alloy Steel Pipes (UNS K41545 Series)

ASTM A335 P5 alloy steel seamless pipes, manufactured from UNS K41545, including grades P5b (UNS K41545B) and P5c (UNS K41545C), are chromium–molybdenum (Cr-Mo) alloy steel pipes designed for elevated temperature and high-pressure service. These grades exhibit strong thermal stability, exceptional creep resistance, and excellent oxidation protection, making them ideal for demanding applications in refineries, power plants, petrochemical units, boilers, and heater tubes.

The increased chromium and molybdenum content in P5, P5b, and P5c significantly enhances corrosion resistance and mechanical strength at high temperatures. These pipes are supplied in seamless form to meet stringent industrial requirements for durability, reliability, and safe long-term operation.

Key Features

• ASTM A335 standard Cr-Mo alloy seamless pipes
• Grades: P5, P5b, P5c (UNS K41545 Series)
• Superior high-temperature strength and creep resistance
• Excellent oxidation and corrosion resistance
• Suitable for high-pressure environments
• Dimensions available in hot finished and cold drawn conditions
• Ideal for boiler tubes, heat exchangers, and refinery heater lines

Equivalent Grade

Available Sizes

• NPS (Nominal Pipe Size): 1/8″ to 30″+
• OD (Outside Diameter): ~19 mm to >600 mm (0.75″ to >24″)
• Schedules (WT):  STD, SCH 40, SCH 80 (XS), SCH 160, and XXS

ASTM A335 P5 / P5b / P5c Chemical Composition

Element	P5 (%)	P5b (%)	P5c (%)
Carbon	0.15 max	0.15 max	0.15 max
Manganese	0.30 – 0.60	0.30 – 0.60	0.30 – 0.60
Phosphorus	0.025 max	0.025 max	0.025 max
Sulfur	0.025 max	0.025 max	0.025 max
Silicon	0.50 – 1.00	0.50 – 1.00	0.50 – 1.00
Chromium	4.0 – 6.0	4.0 – 6.0	4.0 – 6.0
Molybdenum	0.45 – 0.65	0.45 – 0.65	0.45 – 0.65

ASTM A335 Gr P5 / P5b / P5c Mechanical Properties

Property	P5	P5b	P5c
Tensile Strength	415 MPa min	380 MPa min	380 MPa min
Yield Strength	205 MPa min	205 MPa min	205 MPa min
Elongation	30% min	30% min	30% min
Hardness	91 HRB max	91 HRB max	91 HRB max

Gr P5 / P5b / P5c Physical Properties

Property	Value
Density	7.85 g/cm³
Thermal Conductivity	45 W/m-K
Electrical Resistivity	0.60 µΩ·m
Specific Heat	460 J/kg-K
Modulus of Elasticity	200 GPa
Melting Point	1425–1510°C

Type of ASTM A335 P5 Tubes

• Seamless Alloy Steel Pipes
• Hot Finished Pipes
• Cold Drawn Seamless Pipes

Applications

• Power generation boiler tubes
• Refinery heater pipes
• Petrochemical processing units
• Steam pipelines and superheaters
• Heat exchangers and pressure vessels
• High-temperature service piping